A Group III nitride compound semiconductor light-emitting device is known as a light-emitting diode for emitting light in a color ranging from blue to green. The Group III nitride compound semiconductor light-emitting device is also used as a light-emitting diode for emitting light at a shorter wavelength (in a range of from near-ultraviolet to ultraviolet) than the wavelength of visible light.
Although the Group III nitride compound semiconductor light-emitting device emitting light at such a short wavelength is heretofore known, higher light-emitting efficiency and output have been required of the light-emitting device recently.